qemu/ui/vnc-clipboard.c
Fiona Ebner ebfbf39467 ui/vnc-clipboard: fix inflate_buffer
Commit d921fea338 ("ui/vnc-clipboard: fix infinite loop in
inflate_buffer (CVE-2023-3255)") removed this hunk, but it is still
required, because it can happen that stream.avail_in becomes zero
before coming across a return value of Z_STREAM_END in the loop.

This fixes the host->guest direction of the clipboard with noVNC and
TigerVNC as clients.

Fixes: d921fea338 ("ui/vnc-clipboard: fix infinite loop in inflate_buffer (CVE-2023-3255)")
Reported-by: Friedrich Weber <f.weber@proxmox.com>
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
Acked-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20231122125826.228189-1-f.ebner@proxmox.com>
2023-12-04 11:28:26 +04:00

341 lines
9.6 KiB
C

/*
* QEMU VNC display driver -- clipboard support
*
* Copyright (C) 2021 Gerd Hoffmann <kraxel@redhat.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "vnc.h"
#include "vnc-jobs.h"
static uint8_t *inflate_buffer(uint8_t *in, uint32_t in_len, uint32_t *size)
{
z_stream stream = {
.next_in = in,
.avail_in = in_len,
.zalloc = Z_NULL,
.zfree = Z_NULL,
};
uint32_t out_len = 8;
uint8_t *out = g_malloc(out_len);
int ret;
stream.next_out = out + stream.total_out;
stream.avail_out = out_len - stream.total_out;
ret = inflateInit(&stream);
if (ret != Z_OK) {
goto err;
}
while (stream.avail_in) {
ret = inflate(&stream, Z_FINISH);
switch (ret) {
case Z_OK:
break;
case Z_STREAM_END:
*size = stream.total_out;
inflateEnd(&stream);
return out;
case Z_BUF_ERROR:
out_len <<= 1;
if (out_len > (1 << 20)) {
goto err_end;
}
out = g_realloc(out, out_len);
stream.next_out = out + stream.total_out;
stream.avail_out = out_len - stream.total_out;
break;
default:
goto err_end;
}
}
*size = stream.total_out;
inflateEnd(&stream);
return out;
err_end:
inflateEnd(&stream);
err:
g_free(out);
return NULL;
}
static uint8_t *deflate_buffer(uint8_t *in, uint32_t in_len, uint32_t *size)
{
z_stream stream = {
.next_in = in,
.avail_in = in_len,
.zalloc = Z_NULL,
.zfree = Z_NULL,
};
uint32_t out_len = 8;
uint8_t *out = g_malloc(out_len);
int ret;
stream.next_out = out + stream.total_out;
stream.avail_out = out_len - stream.total_out;
ret = deflateInit(&stream, Z_DEFAULT_COMPRESSION);
if (ret != Z_OK) {
goto err;
}
while (ret != Z_STREAM_END) {
ret = deflate(&stream, Z_FINISH);
switch (ret) {
case Z_OK:
case Z_STREAM_END:
break;
case Z_BUF_ERROR:
out_len <<= 1;
if (out_len > (1 << 20)) {
goto err_end;
}
out = g_realloc(out, out_len);
stream.next_out = out + stream.total_out;
stream.avail_out = out_len - stream.total_out;
break;
default:
goto err_end;
}
}
*size = stream.total_out;
deflateEnd(&stream);
return out;
err_end:
deflateEnd(&stream);
err:
g_free(out);
return NULL;
}
static void vnc_clipboard_send(VncState *vs, uint32_t count, uint32_t *dwords)
{
int i;
vnc_lock_output(vs);
vnc_write_u8(vs, VNC_MSG_SERVER_CUT_TEXT);
vnc_write_u8(vs, 0);
vnc_write_u8(vs, 0);
vnc_write_u8(vs, 0);
vnc_write_s32(vs, -(count * sizeof(uint32_t))); /* -(message length) */
for (i = 0; i < count; i++) {
vnc_write_u32(vs, dwords[i]);
}
vnc_unlock_output(vs);
vnc_flush(vs);
}
static void vnc_clipboard_provide(VncState *vs,
QemuClipboardInfo *info,
QemuClipboardType type)
{
uint32_t flags = 0;
g_autofree uint8_t *buf = NULL;
g_autofree void *zbuf = NULL;
uint32_t zsize;
switch (type) {
case QEMU_CLIPBOARD_TYPE_TEXT:
flags |= VNC_CLIPBOARD_TEXT;
break;
default:
return;
}
flags |= VNC_CLIPBOARD_PROVIDE;
buf = g_malloc(info->types[type].size + 4);
buf[0] = (info->types[type].size >> 24) & 0xff;
buf[1] = (info->types[type].size >> 16) & 0xff;
buf[2] = (info->types[type].size >> 8) & 0xff;
buf[3] = (info->types[type].size >> 0) & 0xff;
memcpy(buf + 4, info->types[type].data, info->types[type].size);
zbuf = deflate_buffer(buf, info->types[type].size + 4, &zsize);
if (!zbuf) {
return;
}
vnc_lock_output(vs);
vnc_write_u8(vs, VNC_MSG_SERVER_CUT_TEXT);
vnc_write_u8(vs, 0);
vnc_write_u8(vs, 0);
vnc_write_u8(vs, 0);
vnc_write_s32(vs, -(sizeof(uint32_t) + zsize)); /* -(message length) */
vnc_write_u32(vs, flags);
vnc_write(vs, zbuf, zsize);
vnc_unlock_output(vs);
vnc_flush(vs);
}
static void vnc_clipboard_update_info(VncState *vs, QemuClipboardInfo *info)
{
QemuClipboardType type;
bool self_update = info->owner == &vs->cbpeer;
uint32_t flags = 0;
if (info != vs->cbinfo) {
qemu_clipboard_info_unref(vs->cbinfo);
vs->cbinfo = qemu_clipboard_info_ref(info);
vs->cbpending = 0;
if (!self_update) {
if (info->types[QEMU_CLIPBOARD_TYPE_TEXT].available) {
flags |= VNC_CLIPBOARD_TEXT;
}
flags |= VNC_CLIPBOARD_NOTIFY;
vnc_clipboard_send(vs, 1, &flags);
}
return;
}
if (self_update) {
return;
}
for (type = 0; type < QEMU_CLIPBOARD_TYPE__COUNT; type++) {
if (vs->cbpending & (1 << type)) {
vs->cbpending &= ~(1 << type);
vnc_clipboard_provide(vs, info, type);
}
}
}
static void vnc_clipboard_notify(Notifier *notifier, void *data)
{
VncState *vs = container_of(notifier, VncState, cbpeer.notifier);
QemuClipboardNotify *notify = data;
switch (notify->type) {
case QEMU_CLIPBOARD_UPDATE_INFO:
vnc_clipboard_update_info(vs, notify->info);
return;
case QEMU_CLIPBOARD_RESET_SERIAL:
/* ignore */
return;
}
}
static void vnc_clipboard_request(QemuClipboardInfo *info,
QemuClipboardType type)
{
VncState *vs = container_of(info->owner, VncState, cbpeer);
uint32_t flags = 0;
if (type == QEMU_CLIPBOARD_TYPE_TEXT) {
flags |= VNC_CLIPBOARD_TEXT;
}
if (!flags) {
return;
}
flags |= VNC_CLIPBOARD_REQUEST;
vnc_clipboard_send(vs, 1, &flags);
}
void vnc_client_cut_text_ext(VncState *vs, int32_t len, uint32_t flags, uint8_t *data)
{
if (flags & VNC_CLIPBOARD_CAPS) {
/* need store caps somewhere ? */
return;
}
if (flags & VNC_CLIPBOARD_NOTIFY) {
QemuClipboardInfo *info =
qemu_clipboard_info_new(&vs->cbpeer, QEMU_CLIPBOARD_SELECTION_CLIPBOARD);
if (flags & VNC_CLIPBOARD_TEXT) {
info->types[QEMU_CLIPBOARD_TYPE_TEXT].available = true;
}
qemu_clipboard_update(info);
qemu_clipboard_info_unref(info);
return;
}
if (flags & VNC_CLIPBOARD_PROVIDE &&
vs->cbinfo &&
vs->cbinfo->owner == &vs->cbpeer) {
uint32_t size = 0;
g_autofree uint8_t *buf = inflate_buffer(data, len - 4, &size);
if ((flags & VNC_CLIPBOARD_TEXT) &&
buf && size >= 4) {
uint32_t tsize = read_u32(buf, 0);
uint8_t *tbuf = buf + 4;
if (tsize < size) {
qemu_clipboard_set_data(&vs->cbpeer, vs->cbinfo,
QEMU_CLIPBOARD_TYPE_TEXT,
tsize, tbuf, true);
}
}
}
if (flags & VNC_CLIPBOARD_REQUEST &&
vs->cbinfo &&
vs->cbinfo->owner != &vs->cbpeer) {
if ((flags & VNC_CLIPBOARD_TEXT) &&
vs->cbinfo->types[QEMU_CLIPBOARD_TYPE_TEXT].available) {
if (vs->cbinfo->types[QEMU_CLIPBOARD_TYPE_TEXT].data) {
vnc_clipboard_provide(vs, vs->cbinfo, QEMU_CLIPBOARD_TYPE_TEXT);
} else {
vs->cbpending |= (1 << QEMU_CLIPBOARD_TYPE_TEXT);
qemu_clipboard_request(vs->cbinfo, QEMU_CLIPBOARD_TYPE_TEXT);
}
}
}
}
void vnc_client_cut_text(VncState *vs, size_t len, uint8_t *text)
{
QemuClipboardInfo *info =
qemu_clipboard_info_new(&vs->cbpeer, QEMU_CLIPBOARD_SELECTION_CLIPBOARD);
qemu_clipboard_set_data(&vs->cbpeer, info, QEMU_CLIPBOARD_TYPE_TEXT,
len, text, true);
qemu_clipboard_info_unref(info);
}
void vnc_server_cut_text_caps(VncState *vs)
{
uint32_t caps[2];
if (!vnc_has_feature(vs, VNC_FEATURE_CLIPBOARD_EXT)) {
return;
}
caps[0] = (VNC_CLIPBOARD_PROVIDE |
VNC_CLIPBOARD_NOTIFY |
VNC_CLIPBOARD_REQUEST |
VNC_CLIPBOARD_CAPS |
VNC_CLIPBOARD_TEXT);
caps[1] = 0;
vnc_clipboard_send(vs, 2, caps);
if (!vs->cbpeer.notifier.notify) {
vs->cbpeer.name = "vnc";
vs->cbpeer.notifier.notify = vnc_clipboard_notify;
vs->cbpeer.request = vnc_clipboard_request;
qemu_clipboard_peer_register(&vs->cbpeer);
}
}